1. Field of the Invention
This invention relates generally to a vise for clamping a workpiece and more particularly to a vise capable of clamping a workpiece having an angularly disposed member wherein the angled portion of the workpiece is clamped between a curvilinear surface and a pivotable surface.
2. Description of the Related Art
There are a variety of clamping devices available in the art for clamping a workpiece during machining or other manufacturing operations. Most of these devices secure the workpiece by clamping it between two or more jaws which are capable of movement relative to one another. The jaws may have fixed or moveable bearing surfaces which contact the workpiece. Where moveable bearing surfaces are utilized, they are typically designed to pivot in some fashion to conform to irregularly shaped workpieces.
Angled extrusions, such as those frequently seen in aircraft structural parts, present a particularly difficult clamping task to the machinist. If the base of an angled extrusion is to be machined, the angled portion of the extrusion must be clamped. For accurate machining, the base of the angled extrusion must remain parallel to and flush with the sacrificial material that is typically inserted between the vise jaws and the angled extrusion base. Ordinary vises tend to impart clamping forces at different locations on the angled portion of the angled extrusion, thereby creating a net moment which will tend to move some portion of the base out of parallel with the sacrificial material. Angled extrusions also typically require the machinist to manually adjust the vise jaws to approximately conform to the angle of the angled portion of the extrusion. This is a tedious time consuming process which, depending upon the size of the workpiece and vises involved, may involve a blind operation since the machinist may not be able to visually verify that the jaws have closely matched the angle of the extrusion. Even if the operator carefully manually positions the vise jaws to secure the angled extrusion in a vise which has pivoting bearing surfaces, the pivoting bearing surfaces may have a tendency to rotate during machining which will cause misalignment of the workpiece.